CCD (Charge Coupled Device) type solid state imaging devices or CMOS (Complementary Metal Oxide Semiconductor) type solid state imaging devices are distributed as solid state imaging devices for imaging a subject. A dynamic range of the solid state imaging devices for an incident light is being gradually enhanced by the improvement of semiconductor technologies. However, it is not so uncommon that an incident light exceeding a preset dynamic range is generated in a situation where a solid state imaging device is actually utilized. Therefore, a technology for extending a dynamic range is being actively investigated.
For example, Patent Document 1 discloses an imaging apparatus provided with a solid state imaging device, in which the solid state imaging device includes a pixel that performs long-term exposure, and a pixel that starts short-term exposure during a period where the long-term exposure is being performed. The imaging apparatus combines an image obtained with the long-term exposure and an image obtained with the short-term exposure to extend a dynamic range.
Further, Patent Document 2 discloses an imaging apparatus provided with a solid state imaging device in which pixels that perform long-term exposure and pixels that perform short-term exposure multiple times and conduct outputting each time the short-term exposure is performed. The pixels are arranged in a grid pattern. The imaging apparatus averages a plurality of images obtained with the short-term exposure to correct camera shake. The imaging apparatus combines an image after averaging and an image obtained with the long-term exposure to extend a dynamic range.
It is necessary for the imaging apparatuses to perform photographing several times while changing a ratio of the long-term exposure and the short-term exposure in order to obtain plural kinds of image data having different dynamic ranges for the same subject. However, a photographing environment changes every moment. For example, the subject may move or the sun may disappear behind the clouds between photographings. Therefore, it is not easy to obtain image data having different dynamic ranges for the same subject.
After the photographing is ended, when an image data with a desired dynamic range extension ratio can be generated, it becomes possible to obtain an expected image. However, until now, an imaging apparatus with such a function is not present.